Phases of matter and vapor pressure.

Essay by ilnet2000High School, 10th grade November 2003

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How do we describe phase changes?

What are the phases of matter?

The four phases of matter include:





A phase change involves a change in the physical state of a substance from one phase to another such as: or vice versa

oSolid- liquid

oLiquid- gas

oSolid - gas


The physical state of matter characterized by particles that appear to vibrate about fixed points. Particles of a solid (crystalline) are arranged in a compact, three dimensional pattern called a lattice. Because the particles of a solid are held together y strong attractive forces, solids have a definite shape and volume


The physical state of matter characterized by particles that value the ability to slide past each other. This is because the particles of a liquid are not held together as tightly as those of a solid. The particles of a liquid are generally farther apart than they are in solids; therefore, they have more room to move around.

The mobility of the particles of a liquid causes liquids to have no definite shape, but a definite volume


The physical state of matter characterized by particles that are separated by large distances. This allows the molecules of a gas to have the greatest mobility of all the other states of matter (except plasma). Because molecules of a gas are separated by large distances (with little or no attraction towards each other) gas can expand to fill their containers. In other words gases have no definite shape or volume. Any given volume of a gas is mostly empty space


oOrderly arranged

oVery little mobility- vibrate

oDefinite shape and volume


oLess orderly arranged

oMore mobility

oNo definite shape

oDefinite volume


oCompletely disorganized

oGreatest mobility

oNo definite shape or volume

Any substance can (in theory)...